The answer to the first question is yes. According to 900.12(e)(5)(i)(A), if the physicist (or the facility) learns that the AEC cannot perform as required, the facility should first attempt to correct the problem by adjusting the density settings on the AEC. If that is unsuccessful, the facility may use manual mode technique charts. Manual mode would also be acceptable under the complete failure situation raised by the question. Hence, the facility can use manual techniques for 30 days while the non-functioning AEC is being repaired and can continue to use the unit on patients during this period.
Regarding the second question, because the AEC is considered to be a major component of the mammography unit, the physicist must recheck the unit after the problem has been corrected in accordance with 900.12(e)(10).